N1 (rocket)

The N1 (from Ракета-носительRaketa-nositel', "Carrier Rocket"; Cyrillic: Н1, GRAU index: 11A52, Sheldon: G-1-e, DoD: SL-15) was a super heavy-lift launch vehicle of the Soviet space program intended for crewed travel to the Moon and beyond. All four launch attempts between 1969 and 1972 failed. Studied and designed by OKB-1 since 1959, it was the counterpart to the US Saturn V.

A five-stagekerolox-fuelled rocket, its Block A was the most powerful rocket stage flown for over 50 years, at 45 meganewtons of thrust, until the SpaceX Super Heavy. Block A's large cluster of thirty NK-15 engines, prone to individual failures, was managed by KORD, an analog computer which shut down engines opposite the failure, to maintain attitude control. Block B and V used eight and four hot staged engines respectively, planned to bring the rocket to low Earth orbit. Dangers of the complex engine cluster and fuel feeder systems were not discovered earlier as static fires were not conducted on the Block A. Its second test flight resulted in one of the largest conventional explosions ever, that disabled its Site 110launch pad at Baikonur Cosmodrome for 18 months.

The N1-L3 aimed to compete with the US Apollo program for a crewed Moon landing, using a similar lunar orbit rendezvous method. The rocket had three stages, carrying the L3 lunar payload into low Earth orbit with two cosmonauts. The L3 contained the Block G trans-lunar injection stage; Block D for mid-course corrections, lunar orbit insertion, and initial surface descent; single-pilot LK lander; and two-pilot Soyuz 7K-LOK orbital spacecraft for return to Earth.

The N1 started development in October 1965, almost four years after the Saturn V. The project was derailed by the death of its chief designer Sergei Korolev in 1966; the program was suspended in 1974 and canceled in 1976. The TMK project of crewed Mars and Venusflybys also relied on the N1. OKB-1 later developed Energia, the only Soviet super-heavy lift rocket to reach orbit, flying in 1987 and 1988. Details of the Soviet crewed lunar programs were kept secret until the USSR was nearing collapse in 1989. From 2013, the NK-33 engines, built for the N1F improvement cancelled in 1974, were adapted to the smaller US Orbital SciencesAntares 100 rockets and Russian Soyuz 2.1v rockets.